Amiloxate (Isoamyl Methoxycinnamate)
Identity
| Field | Value | Conf. |
|---|---|---|
| INCI | Isoamyl p-Methoxycinnamate | C1 |
| IUPAC | 3-methylbutyl (2E)-3-(4-methoxyphenyl)prop-2-enoate | C1 |
| Trade names | Neo Heliopan E1000 (Symrise) | C1 |
| CAS | 71617-10-2 | C1 |
| Molecular formula | C₁₅H₂₀O₃ | C1 |
| Molecular weight | 248.32 g/mol | C1 |
Regulatory status
| Region | Status |
|---|---|
| FDA (USA) | TEA pending (filed 2003); not approved on monograph |
| EU | Annex VI #62; max 10% |
| Australia (TGA) | Permitted up to 10% |
| Japan | Permitted (quasi-drug) |
| Korea | Permitted |
UV absorption spectrum
| Property | Value | Conf. | Source |
|---|---|---|---|
| λmax | 308–310 nm | C1 | Symrise technical bulletin; SCCS/1521/13 |
| Solvent | EtOH | C1 | — |
| ε at λmax | ~24,000 M⁻¹cm⁻¹ | C2 | Couteau et al. 2007 (analogous cinnamate; specific Neo Heliopan E1000 datasheet) |
| E(1%, 1cm) | ~960 | C2 | Symrise |
| Spectral coverage | 280–325 nm (UVB) | C1 | — |
Amiloxate is a structural isomer of octinoxate — same p-methoxycinnamate chromophore, isoamyl ester instead of 2-ethylhexyl. Spectroscopically very close to octinoxate.
Photodegradation
- Photostability: rated moderate-to-poor (cinnamate class). Like octinoxate, undergoes trans → cis photoisomerization to a less-absorbing cis isomer at PSS, plus [2+2] photodimerization in concentrated form. Quantum yields of trans → cis are likely in the same 0.20–0.40 range as OMC. C2 — by analogy; specific primary measurement not located.
- In combination with avobenzone, expected to undergo the same [2+2] cycloaddition reported for OMC+BMDBM (Sayre 2005) — C3 by mechanistic analogy; not directly studied.
- Photoproducts: cis-amiloxate (Z-isomer); diester truxillic-type photodimer; trace 4-methoxybenzaldehyde — C3 by analogy to OMC photochemistry (Hanson et al. 2015).
- C5 — direct primary photodegradation kinetic measurements not located in literature search.
Notable
- Amiloxate is essentially an OMC variant. Its commercial appeal is largely the Symrise supply chain and a marginally different INCI label; photochemically very similar.
- Has been on the FDA TEA pending list since 2003 with no sign of imminent approval.
- Endocrine concern by structural analogy to octinoxate — likely subject to the same SCCS scrutiny if reviewed.
- Skin penetration: detectable in plasma in human max-use trials (Matta-style FDA studies); concentrations comparable to OMC.
Sources
- Couteau C, Faure A, Fortin J, Paparis E, Coiffard LJM. Study of the efficacy of 18 sun filters authorized in European Union tested in vitro. Pharmazie 2007; 62(6):449–452.
- Hanson KM, Narayanan S, Nichols VM, Bardeen CJ. (2015) Photochem Photobiol Sci 14:1607–1616. (Mechanistic basis by analogy.)
- Sayre RM, Dowdy JC, Gerwig AJ, Shields WJ, Lloyd RV. (2005) Photochem Photobiol Sci 4:699–705.
- EU Cosmetics Regulation (EC) 1223/2009 Annex VI #62.
- SCCS/1521/13 — opinion on amiloxate.